Use CDCVF2510A as a Replacement for
this Device
Phase-Lock Loop Clock Distribution for
Synchronous DRAM Applications
Distributes One Clock Input to Four Banks
of Four Outputs
Separate Output Enable for Each Output
Bank
External Feedback Pin (FBIN) Is Used to
Synchronize the Outputs to the Clock Input
On-Chip Series-Damping Resistors
No External RC Network Required
Operates at 3.3-V VCC
Packaged in Plastic 48-Pin Thin Shrink
Small-Outline Package

description
The CDC2516 is a high-performance, low-skew,
low-jitter, phase-lock loop (PLL) clock driver. It
uses a PLL to precisely align, in both frequency
and phase, the feedback output (FBOUT) to the
clock (CLK) input signal. It is specifically designed
for use with synchronous DRAMs. The CDC2516
operates at 3.3-V VCC and provides integrated
series-damping resistors that make it ideal for
driving point-to-point loads.
Four banks of four outputs provide 16 low-skew,
low-jitter copies of the input clock. Output signal
duty cycles are adjusted to 50 percent,
independent of the duty cycle at the input clock.
Each bank of outputs can be enabled or disabled
separately via the 1G, 2G, 3G, and 4G control
inputs. When the G inputs are high, the outputs
switch in phase and frequency with CLK; when the
G inputs are low, the outputs are disabled to the
logic-low state.
Unlike many products containing PLLs, the CDC2516 does not require external RC networks. The loop filter
for the PLL is included on-chip, minimizing component count, board space, and cost.
Because it is based on PLL circuitry, the CDC2516 requires a stabilization time to achieve phase lock of the
feedback signal to the reference signal. This stabilization time is required following power up and application
of a fixed-frequency, fixed-phase signal at CLK, as well as following any changes to the PLL reference or
feedback signals. The PLL may be bypassed for test purposes by strapping AVCC to ground.
The CDC2516 is characterized for operation from 0°C to 70°C.